Packings of Styrofoam are widely used to support the ends of sides of an electronic product, such as a home video unit, a car radio, or a cartridge for a copy machine, in a cardboard box. The packings act as a cushion to protect the product against damage if it is shocked during transportation or handling. Styrofoam, however, is derived from petroleum resources, which are limited. In addition, Styrofoam is awkward when it is disposed as rubbish. So it is preferable to avoid using Styrofoam if possible. Another material used for the same purpose is pieces of corrugated paper stuck together. Corrugated paper is reclaimable, and in this respect it is preferable to Styrofoam. Pieces of corrugated paper stuck together, however, take a relatively long time to prepare. Also it is costly to prepare them. In addition, they do not provide sufficient cushioning effect.